A 3D printing device includes a printing substrate, a movable printing head configured for additively producing from a modelling material a component on the printing substrate, and a flexible printing space cover which, proceeding from the printing head, spans the printing substrate such that a closed printing space is formed between the printing head and the printing substrate, wherein a printing nozzle of the printing head for applying the modelling material protrudes into the printing space. A support structure of the device includes flexible support rods which run from the printing head to the printing substrate and which hold the printing space cover above the printing substrate.